It is narrated from Sayyiduna Zayd bin Arqam (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A woman cannot fulfil the right of Allah upon her until she fulfils the right of her husband, to the extent that even if she is on a camel's saddle and her husband asks her for intimacy, she does not refuse."
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 5065